Radial brush seal for heat exchangers



April 1951 w. D. YERRICK ETAL RADIAL BRUSH SEAL FOR HEAT EXCHANGERS Filed Jan. 15, 1949 Patented Apr. 17, l951 RADIAL BRUSH SEAL FOR HEAT EXCHANGERS William D. Yerrick and Sven Holm, Wellsville,

N. Y., assignors to The Air Preheater Corporation, New York, N. Y.

Original application October 10, 1947, Serial No. 779,044. Divided and this application January 15, 1949, Serial No. 71,144 v p 7 The present invention relates to improved radial seals for use between the rotor and encloslng housing of a rotary regenerative air preheater or similar apparatus.

. In a rotary regenerative heater of the Ljungstrom type a cylindrical rotor ha compartments carrying metallic heat transfer plates which as the rotor turns are first exposed to heating gases and then disposed in the air passage to impart the absorbed heat to the air. The rotor is surrounded by a housing having end or sector plates formed with openings to provide for the flow of gas and air. To prevent the mingling of the two fluids the partitions forming the rotor compartments are provided with radial seals that wipe against the imperforate portions ofthe sector.

3 Claims. (01. 257-6) ing the radial seals from brushes whose bristles are made of metal or other suitable material and will be best understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawings in which:

Figure 1 is a sectional elevational view in diagrammatic form of a rotary regenerative air preheater embodying the present invention.

Figure 2 is an elevational view on an enlarged scale as seen on the line 22 of Figure 3 illustrating one of the brush type radial seals in cooperative relation with the partitions that form the rotor compartments carrying heat transfer plates.

Figure 3 is a view on an enlarged scale as viewed on line 3-3 in Figure 2 of part of the rotor embracing one complete compartment and parts of adjacent compartment on either side thereof and shows the relation of the radial seals to the partitions.

Figure 4 is a perspective view of one of the brush elements which make up the radial seals.

In the drawings the numeral I designates the cylindrical shell of a rotor divided into sector shaped compartments by radial partitions I I connecting it with the rotor post I2 which is driven by a motor and reduction gearing I3 to turn the rotor slowly about its axis. ments contain regenerative heat transfer ma- The rotor compartterial in the form of closely spaced metallic plates I4 which first absorb heat from hot gases entering the preheater through a duct I5 from a boiler or other source to be discharged after passing over the heat transfer plates I4 through an outlet duct- I6 to which an induced draft fan (not shown) is connected. As the rotor turns slowly about its axis, the heated plates I4 aremoved sector plates 2i which are apertured at 22;and23 to admit and dischargexstreams of gas andair flowing through the preheater. In order that the streams of gas and air may not commingle, a portion of the rotor at least equal to but usually greater in circumferential extent than one rotor compartment must be isolated Or blocked off between the gas and air passages. As illustrated, radial seals designated as a whole by the numeral 24 (Figs. 2 and 3) are provided in cooperative relation between the radial partitions I I and the sector plates 2i whose imperforate portions 25 must be at least'slightly greater than the width of the compartments in the rotor. In order that the streams of gas and air may not by-pass the heat transfer surface I4 by flowing in the annular clearance space 26 between the rotor shell I0 and the housing 20 it is customary to provide circumferential seals indicated diagrammatically at 30 on the shell III-which Wipe against the sector plates 2I or allied parts so as to seal off the space 26 at both ends of the rotor.

In accordance with the present invention the radial seals 24 are essentially brushes with bristles 3| of some suitable heat resistin alloy. The radial seals 24 are in the form of blocks or pads of wire brush made up of a plurality of sections 60' one of which is shown in perspective view in Fig. 4. These are mounted on the imperforate portions 25 of the sector plates 2| so as to face the rotor. Mounted on the end edges of the radial partition plates II are wear shoes BI of cast iron or heat resisting alloy against which the brushes contact. The radial brush seal 24 made up of a number of pads 68 radially aligned has a circumferential width slightly greater than that of a rotor compartment so that at least one wear shoe BI is always in contact with the seal 24 to prevent cross flow of the streams of gas and air over the ends of the rotor. The wear shoes 6| are mounted on the ends of partitions H by bolts 63 passing through elongated holes 64 to provide for vertical adjustment to compensate for the wear of brushes 60. The side edges of the brush sections 60 may be parallel as illustrated in Fig. 4 so that the radial seal may be made up of a number of similar sections, whereas, if the sides were radial the component sections of the radial seal located between the rotor post and shell would be of similar shape but different in size because of the divergence caused by the radial construction.

The radial seals described offer no obstruction on the ends of the partitions to flow of fluids.

The wear shoes 6| on the diaphragrns II have structural strength and cannot be damaged by being walked on when an operative is replacing heat transfer plates or standing on the top of the rotor to do other work. The sealing brushes 60 being mounted on the inner faces of the sector plates 2| are concealed thereby and thus protected from damage. As described above the bristles form a multi-labyrinth seal with very high resistance against flow of gas or air and therefore prevent leakage at relatively high pressure difierentials.

The subject matter of this application is divided from that filed in our name on October 10, 1947, under Serial No. 779,044.

What we claim is:

1. In a regenerative air preheater or the like having a rotor made up of a cylindrical shell joined to a rotor post by radial partitions forming compartments that carry heat transfer material, and a housing surrounding the rotor and provided opposite the ends of the latter with sector plates extending transversely across the rotor and formed with apertures for the flow of heating gases and air to and through the rotor; brush sealing means mounted on the inner surfaces of the imperforate portions of said sector plates between the openings therein so as to face the rotor and being of an extent circumferentially of the rotor to be in simultaneous contact with the entire radial extent of the end edges of two contiguous partitions during turning of the rotor.

,2. In a regenerative air preheater or the like having a rotor made up of a cylindrical shell joined to a rotor post by radial partitions forming compartments that carry heat transfer material, and a housing surrounding the rotor and provided opposite the ends of the latter with sector plates formed with apertures for the flow of heating gases and air to and through the rotor; brush sealing mean mounted on the inner surfaces of the imperforate portions of said sector plates between the openings therein so as to face the rotor; and wear shoes mounted on the end edges of said rotor partitions so as to wipe against said brush means as the rotor turns.

3. Radial sealing means as defined in claim 2 wherein the wear shoes are adjustably mounted.

WILLIAM D. YERRICK. SVEN HOLM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Whitney Nov. 16, 1943 

